Flexible support structure for end winding connections

ABSTRACT

In a dynamoelectric machine, an insulating end winding support providing unidirectional flexibility in response to axial thermal excursions of the end winding members. An insulating support ring is concentrically mounted on the dynamoelectric machine while a floating outer support is fixed to the end winding members. A spacer is positioned between the first support ring and the floating support and a kinked tie wrap is secured around the first support ring, the floating outer support and the spacer. A second embodiment requires the use of two concentrically mounted support rings with a spacer there between secured with a kinked tie wrap. A third embodiment discloses a flanged support ring and a &#39;&#39;&#39;&#39;phase jumper&#39;&#39;&#39;&#39; with a spacer there between secured by a kinked tie wrap.

United States Patent Drexler et al.

[ 1 Sept. 12,1972

[S4] FLEXIBLE SUPPORT STRUCTURE FOR END WINDING CONNECTIONS [73]Assignee: General Electric Company [22] Filed: June 14, I971 [21] Appl.No.: 152,698

[52] US. Cl ..310/260, 310/270 [51 Int. Cl. ..II02k 3/46 [58] Field ofSearch ..310/260, 270

[56] References Cited UNITED STATES PATENTS 3,089,048 5/1963 Bahn et al..310/260 3,344,297 9/1967 Bishop et al. ..310/260 FOREIGN PATENTS ORAPPLICATIONS 853,251 11/1960 Great Britain ..310/260 Primary Examiner-D.X. Sliney Attorney-William C. Crutcher et al.

[5 7] ABSTRACT In a dynamoelectric machine, an insulating end windingsupport providing unidirectional flexibility in response to axialthermal excursions of the end winding members. An insulating supportring is concentrically mounted on the dynamoelectric machine while afloating outer support is fixed to the end winding members. A spacer ispositioned between the first support ring and the floating support and akinked tie wrap is secured around the first support ring, the floatingouter support and the spacer. A second embodiment requires the use oftwo concentrically mounted support rings with a spacer there betweensecured with a kinked tie wrap. A third embodiment discloses a flangedsupport ring and a phase jumper" with a spacer there between secured bya kinked tie wrap.

11 Claims, 5 Drawing Figures PATENTED 12 I97? 3.691.416

SHEET 1 [IF 2 INVENTORSZ l3 KARL F. DREXLER,

EDWARD E. GIBBS,

BY WM THEIR ATTORNEY.

PATENTEUSEP 12 I972 3. 691 4 l 6 SHEET 2 0F 2 FIGS INVENTORS KARL F.DREXLER, EDWARD E. GIBBS,

BY W M THEIR ATTORNEY FLEXIBLE SUPPORT STRUCTURE FOR END WINDINGCONNECTIONS BACKGROUND OF THE INVENTION the projecting portions of thestator bars which extend outwardly from slots in the stator core. Thepurpose of end windings is to reverse the direction of stator bars. Onetype of end winding, known as a series loop" is used to reverse thedirection of an emerging stator bar and to circumferentially displacethe bar so that it may re-enter the stator core in a 'slot which may be120 to 180 circumferentially displaced from the slot from which itemerged. Another type of end winding is a phase jumper which is used forlimited circumferential displacement, perhaps in order of 30, when it isrequired by the phase winding pattern. An end turn region may have anumber of stator bars emerging from the stator core slots, the bar endsof which have to be interconnected, insulated and supported. Typically,in large dynamoelectric machines, two stator bars are located in eachstator slot.

The support of the end windings of a dynamoelectric machine is a complexproblem when viewed in the perspective of a complicated series of loopsand convergent, divergent and skewed stator bar ends. Further, thesupport structure must be able to withstand electromagnetic forces,vibrational forces and thermal forces applied by the dynamoelectricmachine. Thermal forces cause axial expansion of the stator bars whichwould cause an undesirable stress buildup in the stator bars if thethermal expansions were rigidly restrained. However, US Pat. No.3,089,048 granted to Bahn et al., on May 7, 1963 and assigned to theassignee of this invention, discloses an expandable bracket which allowsfor thermal breathing. A support member, made of an insulating material,is fixed to the stator frame by means of metal brackets. This type ofconstruction is costly requiring special parts and because of the use ofmetal brackets instead of insulated tie wraps, it is inconsistent withthe general end winding insulation scheme of the dynamoelectric machine.

OBJECTS OF THE INVENTION Accordingly, it is an object of the presentinvention to provide an improved, high strength, insulating supportsystem for stator end windings in an electrically highly stressed regionwhile allowing for axial thermal expansion within the end winding.

It is another object of this invention to retain vibrational forcesbetween support and end windings in radial, tangential and axialdirections by sufficiently rigid integration.

It is another object of this invention to eliminate the use of metal asa construction component in the end winding support system, thusproducing a truly insulated end wind support.

It is still another object of the present invention to provide easyadjustment for any variance in clearance between the support ring andthe end winding connection.

Other objects, advantages and features of the present invention willbecome apparent from the following detailed description of the variousembodiments thereof taken in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial elevation view ofthe side of one end of a dynamoelectric machine showing the end windingregion with the present invention applied thereto.

FIG. 2 is an enlarged side elevation view of the present invention.

FIG. 3 is an enlarged side elevation view of an alternate embodiment ofthe present invention.

FIG. 4 is a partial front elevation view of one end of a dynamoelectricmachine having a phase jumper applied thereto along with the presentinvention.

FIG. 5 is a side elevation view of one end of a dynamoelectric machineshowing the phase jumper applied thereto along with the presentinvention.

SUMMARY OF THE INVENTION An insulating support structure for use in theend winding region of a dynamoelectric machine, which restrains the endwindings in the radial direction while permitting limited movement inthe axial direction. In one embodiment, at least one pair of supportrings having relatively slight differences in diameters are mounted in asubstantially concentric relationship with the stator core. One supportring is fixed to an axial support in the form of a circular flange onthe dynamoelectric machine frame while the other support ring is fixedto a floating outer support member to which end windings are attached.lnterposed strategically between the rings may be a plurality of spacersat which points the rings are tied together by a resin impregnated glasstie. The tie is formed with a slightly kinked portion which allows foraxial movement while restraining radial movement.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, andparticularly referring to FIG. 1, there is shown a partial sideelevation view of the end winding region at one end of a dynamoelectricmachine 11. The stator core 12 includes a circumferential flange 13.Turning within a bore 15 in the stator core is the dynamoelectricmachine rotor 17.

Upper 21 and lower 23 stator bars emerge from the stator core slots (notshown) and along with a series loop 25 determine part of the end windingregion. FIG. 1 shows the stator bars and the series loop all to be inthe same plane but this is done only for the sake of convenience andsimplification in drawing the invention. In practice, the two connectedstator bars and the series loop would all be found in different planes.Bar clips 27 may be used to join the stator bar ends and the series loopconnection.

The manner in which the upper and lower stator bars are fixed to theouter floating support 31 will be reviewed briefly since a variety oftie systems may be used. One such tie system is shown in U.S. Pat. No.3,089,048 granted to Bahn et al., and assigned to the assignee of thepresent invention as previously cited. Another example of a tie systemin the end turn region is shown in U.S. Pat. No. 3,344,297 granted toBishop et al., on Sept. 26, 1967 and assigned to the assignee of thepresent case.

Inthe present case, the upper and lower stator bars have a combinationof conformable spacers 33 and Z rings 35 interposed between the bars inorder to add rigidity to the end winding structure. lnterposed betweenthe lower bar 23 and the outer floating support 31 are a plurality of Lrings 37 having conformable spacers 33 mounted thereon. Upper bands ties41 are wrapped about the upper and lower stator bars and the L" ringswhile lower band ties 43 are wrapped about the L rings (and shims 38where needed) and the outer floating support. Thus the tie about thecommon L rings joins the stator bars and the floating support.Additionally the stator bars and the outer floating support are joinedby glass bolt strap 45. A resin impregnated fiber glass ring 47 may besecured to the floating outer support 31, which may be made of resinimpregnated laminates in a manner disclosed in U.S. Pat. No. 3,566,010issued Feb. 23, 1971 to Drexler and Bishop, and assigned to the assigneeof the present invention.

One embodiment of the present invention is best illustrated in detail inFIG. 2. A first supporting ring 51 concentric with the stator core, isfixed to the circumferential flange 13 by means of a screw 53, while asmaller second support ring 55, also concentric with the stator core, isfixed to the floating outer support 31 by means of a dowel 57. A spacer59 is positioned between the flange 13 and the first support ring 51; asimilar spacer is positioned between the outer support 31 and the secondsupport ring. These spacers 59 may be formed from resin impregnatedlaminates.

A sandwich spacer 61 is positioned between the first and second supportrings and held in a groove 62 formed in the first support ring. A rubbersheathed Glaskyd 1901 spacer (trade name, American Cyanamid) or abearing pad or pin spacer would be suitable but it is preferred that aresin-impregnated felt rubber sandwich spacer be used. The nature of thesandwich spacer is more fully described in U.S. Pat. application No.152,679 filed on behalf of Niko V. Gjaja and of even date with thepresent application and assigned to the assignee of the presentapplication.

The first and second support rings are tied by a glass impregnatedkinked" roving tie wrap 63, the kink 65 being formed as the resin cures.This kink 65 contributes the spring characteristic to the support ringsas will later be more thoroughly described. The second support ring isattached to the outer floating support by means of a glass impregnatedroving tie wrap 67 which passes through hole 71 in the outer floatingsupports. The manner in which this tie is formed is fully disclosed inU.S. Pat. No. 3,566,010 issued Feb. 23, 1971 to Drexler and Bishop andassigned to the assignee of the present invention.

Another embodiment is shown in FIG. 3. Parts similar to those numberedin FIG. 2 will receive like numbers. In this embodiment, the supportring 51 is shown as fixed to the stator core 12. It could also be fixedto a flange on the dynamoelectric machine 11 as shown in FIG. 1. In thisembodiment only one support ring is used and the sandwich spacer 61 isdisposed between the underside of a floating outer support 31 and thesupport ring. The glass impregnated roving tie wrap 63 is drawn aroundthe support ring and through a hole 72 in the floating outer support.There is a kink 65 also in this tie wrap.

In FIGS. 4 and 5 there is shown an insulated end winding designated as aphase jumper 111. A support ring ll3 formed with a flange isconcentrically mounted with respect to the stator core. The flange 115results in a more favorable geometry for axial movement and can also beapplied in any previously mentioned embodiment. Note the upper and lowerstator bars 117 and 119 which emerge from the stator core and areelectrically connected into the phase jumper 1 11.

The support ring 113 is attached to an axially extending outer support121 by means of a glass impregnated roving FIG. 8 tie wrap 123. The wrappasses through a pair of holes 125 in the face of the support ring and athird hole 127 in the outer floating support. There may be a spacer 129disposed between the support ring and the outer floating support. Adowel 131 is used to rigidly mount the support ring 113 to the outerfloating support. Again, the manner in which the support ring isattached to the axial support is shown in U.S. Pat. No. 3,566,010 issuedFeb. 23, 1971 to Drexler and Bishop and assigned to the assignee of thepresent invention.

As is apparent from FIG. 4, the support ring is formed with an innercircumferential groove 135 as well as a series of notched portions 137to accommodate a sandwich spacer 139. Again a Glaskyd sausage could beused, but it is preferred to use the felt rubber sandwich spacer.

The spacer is inserted between the phase jumper 111 and the support ring113, in the groove 135 provided. The phase jumper, the support ring andthe sandwich spacer therebetween are tied together by a pair of glassimpregnated roving tie wraps 141 having a kinked portion 143. There maybe other conventional tie wraps 145 to fasten excess spacers to thesupport ring as shown.

OPERATION OF THE INVENTION The end windings of the dynamoelectricmachine are subjected to forces in the tangential, radial and axialdirection. Radial and tangential forces are constrained by means of theroving tension tie wrap, designated as 63 in FIGS. 1 to 3 and as 141 inFIGS. 4 and 5, as well as by the felt sandwich spacer or the Glaskyd"spacer. l-Iowever, axial movement due to low cycle thermal expansion ispermitted because of the following construction features.

The geometry of the support rings as well as their orientation to oneanother is one contributor allowing axial displacement. As seen in FIGS.1 and 2, when two support rings are used, the cross section height towidth ratio is such that the tie wrap must allow some axial flexing. Inaddition, if the first or outer support ring had a slightly greatercross sectional width than the cross sectional width of the second orinner support ring, then axial flexure will be similar to that laterdescribed for FIGS. 4 and 5. In FIG. 3, since there is only onesupportion which together with a significant cross section height towidth ratio promotes axial movement.

4. The support as recited in claim 2 wherein the end winding membersinclude at least one floating outer support to which a plurality ofstator bars are attached.

5. The support as recited in claim 4 wherein the The constructionfeature which promotes axial 5 kinked tension tie wrap is tied about thefirst support movement due to low cycle thermal expansion is theclearance portion in the tie wrap between the wrap and the supportmembers which gives a spring characteristic to the support ring orrings. The spring characteristic is provided by locating or forming thetie so that it does not contact the sides of the support rings thusforming a spring which may be deflected in its traverse direction. Thistraverse direction being so oriented as to permit axial movement of thefloating members. The above clearance may arise from a kink formed inthe tie or because of the geometry of the supporting rings.

The sandwich spacer between the support rings or between the supportring and outer floating support or between the support ring and phasejumper promotes axially motion forward and backward because theelastomeric or rubber portion of the sandwich allows axial motion.

End winding misalignment may be accommodated by using various sizespacers between supports and supported structures.

While there is shown what is considered to be the preferred embodimentof the invention, it is of course understood that various othermodifications may be made therein, and it is intended to cover in theappended claims all such modifications as fall within the true spiritand scope of the invention.

What is claimed:

1. An insulating support, having flexibility in an axial direction,supporting electrical conductors in the end winding region of adynamoelectric machine, said support comprising:

a fixed support member;

a movable member disposed radially adjacent said fixed member;

a flexible spacer positioned between said fixed member and said movablemember;

a rigid, resin impregnated, radial tie encircling said members and saidspacer; and,

clearances, in the axial direction formed between said tie and the sidesof said members and said spacer whereby limited axial movement ispermitted.

2. An insulating support, having unidirectional flexibility, for the endwinding region of a dynamoelectric machine, said support comprising:

at least one first support ring substantially concentric with saiddynamoelectric machine and fixed thereto;

end winding members adjacent said first support ring;

at least one flexible spacer positioned between said first support ringand said end winding members; and

a kinked tension tie wrap about said support ring,

said end winding members and said spacer whereby relative movement inthe radial direction is prevented while relative axial movementispermitted.

3. The support as recited in claim 2 wherein the spacer is a felt andrubber multi-ply construction.

ring, the spacer and the floating outer support.

6. In a dynamoelectric machine including a stator core having aplurality of stator bars extending generally axially therefrom into anend winding region; an insulating end winding support comprising:

at least one first support ring substantially concentric with saiddynamoelectric machine and fixed thereto;

at least one floating outer support member having the stator barsattached thereto;

a spacer positioned between said first support ring and said floatingouter support member; and

a kinked tension tie wrap about said first support ring, said outerfloating support member and said spacer whereby relative movement in theradial direction is prevented while relative axial movement ispermitted.

7. In a dynamoelectric machine including a stator core having aplurality of stator bars extending generally axially therefrom into anend winding region; an insulating end windin g support comprising:

at least one first support ring substantially concentric with saiddynamoelectric machine and fixed thereto;

at least one floating outer support member having the stator barsattached thereto;

at least one second support ring substantially concentric with saidfirst support ring and fixed to said floating outer support member;

a spacer positioned between said first and second support rings; and

a kinked tension tie wrap about said first and second support rings andsaid spacer whereby relative movement in the radial direction isprevented while relative axial movement is permitted.

8. In a dynamoelectric machine including a stator core having aplurality of end winding members extending generally axially therefrominto an end winding region; an insulating end winding supportcomprising:

a generally axially extending support member;

a first support ring attached to said axially extending support member;

at least one end winding member adjacent said first support ring;

at least one flexible spacer positioned between said end winding memberand said support ring; and,

a rigid, resin impregnated, tie encircling said support ring, saidflexible spacer and said end winding member; and

a clearance formed between said tie and said end winding member, saidspacer and said support ring.

9. The support as defined in claim 8 wherein the end winding member is aphase jumper.

10. The support as defined in claim 8 wherein the support ring has aflange formed on its outer circumference whereby said clearance isformed.

11. The support as defined in claim 8 wherein the tie is kinked wherebysaid clearance is formed.

1. An insulating support, having flexibility in an axial direction,supporting electrical conductors in the end winding region oF adynamoelectric machine, said support comprising: a fixed support member;a movable member disposed radially adjacent said fixed member; aflexible spacer positioned between said fixed member and said movablemember; a rigid, resin impregnated, radial tie encircling said membersand said spacer; and, clearances, in the axial direction formed betweensaid tie and the sides of said members and said spacer whereby limitedaxial movement is permitted.
 2. An insulating support, havingunidirectional flexibility, for the end winding region of adynamoelectric machine, said support comprising: at least one firstsupport ring substantially concentric with said dynamoelectric machineand fixed thereto; end winding members adjacent said first support ring;at least one flexible spacer positioned between said first support ringand said end winding members; and a kinked tension tie wrap about saidsupport ring, said end winding members and said spacer whereby relativemovement in the radial direction is prevented while relative axialmovement is permitted.
 3. The support as recited in claim 2 wherein thespacer is a felt and rubber multi-ply construction.
 4. The support asrecited in claim 2 wherein the end winding members include at least onefloating outer support to which a plurality of stator bars are attached.5. The support as recited in claim 4 wherein the kinked tension tie wrapis tied about the first support ring, the spacer and the floating outersupport.
 6. In a dynamoelectric machine including a stator core having aplurality of stator bars extending generally axially therefrom into anend winding region; an insulating end winding support comprising: atleast one first support ring substantially concentric with saiddynamoelectric machine and fixed thereto; at least one floating outersupport member having the stator bars attached thereto; a spacerpositioned between said first support ring and said floating outersupport member; and a kinked tension tie wrap about said first supportring, said outer floating support member and said spacer wherebyrelative movement in the radial direction is prevented while relativeaxial movement is permitted.
 7. In a dynamoelectric machine including astator core having a plurality of stator bars extending generallyaxially therefrom into an end winding region; an insulating end windingsupport comprising: at least one first support ring substantiallyconcentric with said dynamoelectric machine and fixed thereto; at leastone floating outer support member having the stator bars attachedthereto; at least one second support ring substantially concentric withsaid first support ring and fixed to said floating outer support member;a spacer positioned between said first and second support rings; and akinked tension tie wrap about said first and second support rings andsaid spacer whereby relative movement in the radial direction isprevented while relative axial movement is permitted.
 8. In adynamoelectric machine including a stator core having a plurality of endwinding members extending generally axially therefrom into an endwinding region; an insulating end winding support comprising: agenerally axially extending support member; a first support ringattached to said axially extending support member; at least one endwinding member adjacent said first support ring; at least one flexiblespacer positioned between said end winding member and said support ring;and, a rigid, resin impregnated, tie encircling said support ring, saidflexible spacer and said end winding member; and a clearance formedbetween said tie and said end winding member, said spacer and saidsupport ring.
 9. The support as defined in claim 8 wherein the endwinding member is a phase jumper.
 10. The support as defined in claim 8wherein the support ring has a flange formed on its outer circumferencewhereby said clearAnce is formed.
 11. The support as defined in claim 8wherein the tie is kinked whereby said clearance is formed.